@ -67,7 +67,7 @@ When processing the job, it may also be necessary to fetch supplementary files
such as helper scripts or test inputs and outputs.
such as helper scripts or test inputs and outputs.
Supplementary files are addressed using hashes of their content, which allows
Supplementary files are addressed using hashes of their content, which allows
for simple caching. Requested files are downloaded into the cache on demand.
simple caching. Requested files are downloaded into the cache on demand.
This mechanism is hidden from the job evaluator, which depends on a
This mechanism is hidden from the job evaluator, which depends on a
`file_manager_interface` instance. Because the filesystem cache can be shared
`file_manager_interface` instance. Because the filesystem cache can be shared
between more workers, cleaning functionality is implemented by the Cleaner
between more workers, cleaning functionality is implemented by the Cleaner
@ -77,9 +77,9 @@ program that should be set up to run periodically.
Student submissions are executed inside sandboxing environment to prevent damage of host system and also to restrict amount of used resources. Now only the Isolate sandbox support is implemented in worker, but there is a possibility of easy extending list of supported sandboxes.
Student submissions are executed inside sandboxing environment to prevent damage of host system and also to restrict amount of used resources. Now only the Isolate sandbox support is implemented in worker, but there is a possibility of easy extending list of supported sandboxes.
Isolated is executed in separate Linux process created by `fork` and `exec` system calls. Communication between processes is performed through unnamed pipe with standard input and output descriptors redirection. To prevent Isolate failure there is another safety guard -- whole sandbox is killed when it does not end in `(time + 300) * 1.2` seconds for `time` as original maximum time allowed for the task. However, Isolate should allways end itself in time, so this additional safety should never be used.
Isolate is executed in separate Linux process created by `fork` and `exec` system calls. Communication between processes is performed through unnamed pipe with standard input and output descriptors redirection. To prevent Isolate failure there is another safety guard -- whole sandbox is killed when it does not end in `(time + 300) * 1.2` seconds for `time` as original maximum time allowed for the task. However, Isolate should allways end itself in time, so this additional safety should never be used.
Sandbox in general has to be command line application taking parameters with arguments, standard input or file. Outputs should be written to file or standard output. There no other requirements, worker design is very versatile and can be adapted to different needs.
Sandbox in general has to be command line application taking parameters with arguments, standard input or file. Outputs should be written to file or standard output. There are no other requirements, worker design is very versatile and can be adapted to different needs.
Martin Polanka
8 years ago